1. Field of the Invention
The present invention relates to an intermediate disk for a motor vehicle clutch having friction surfaces on both sides and fastened for rotation with a first shaft, said intermediate disk being arranged between friction facings which are fastened for rotation with a second shaft for generating a frictional engagement between the friction facings and the friction surfaces, and the intermediate disk having recesses in a central area between the friction surfaces.
2. Description of the Related Art
Intermediate disks are used in modern multidisk clutches and are known from practice. The prior art intermediate disk is manufactured, for instance, as a cast part and recesses between the friction surfaces are formed by cores which are to be inserted in the casting mold and guided from the edge of the intermediate disk toward its center. When the clutch is operated, and especially during an engagement process, frictional heat is generated at the friction surfaces when the friction facings move against the friction surfaces. This frictional heat produces a very intensive heating of the intermediate disk, so that a reliable frictional engagement of the clutch is no longer guaranteed. Therefore, the recesses are provided to increase the heat-releasing surface of the intermediate disk. Additionally, the recesses reduce the weight of the intermediate disk and therefore, reduce the mass inertia.
However, for technical reasons related to casting, it is usually not possible, particularly in small clutches such as those for passenger vehicles, to employ casting to provide the recesses in the intermediate disks which are generally very thin. It is for this reason that solid intermediate disks are usually used in clutches with small dimensions.
The recesses could be incorporated in the intermediate disk after casting by machining steps such, for example, as cutting and/or drilling. However, this type of construction of the intermediate disk is very cost-intensive.
The object of the invention is to construct an intermediate disk having recesses between the frictional surfaces such that the intermediate disk is produced economically and such that the intermediate disk can carry off heat successfully while retaining small dimensions typically used in passenger cars.
This problem is solved according to the invention in that the intermediate disk has first and second disk parts that are connected with one another. The first and second disk parts each have one of the friction surfaces and each of the first and second disk parts adjoins recesses arranged through the intermediate disk between the friction surfaces. Furthermore, spacers are arranged between the disk parts.
As a result of this construction, the recesses are freely accessible from the sides of each disk part remote from the friction surfaces, so that they can easily be incorporated in the disk parts or provided during casting. Since the intermediate disk does not require any machining proceeding from its edge to produce the recesses, it is very simple and economical to produce. In addition, the disk parts require only the thickness necessary for a given stability of the intermediate disk. The quantity and dimensions of the spacers are arrangeable so that the intermediate disk is constructed with high stability. Accordingly, small and thin intermediate disks for multiple disk clutches used in passenger vehicles are provided with recesses according to the invention to increase their heat-releasing surface.
The intermediate disk according to an embodiment of the present invention comprises a particularly small number of structural component parts to be assembled when the spacers are manufactured as an integral part with at least one of the first and second disk parts. In the simplest embodiment, the first and second disk parts may be produced together with the spacers by casting in a coreless mold with axial casting ejection.
The intermediate disk according to the invention may be made particularly economically when the spacers are arranged on the side of each of the first and second disk parts remote from the friction surface. According to this embodiment, the first and second disk parts may be identically constructed.
Especially large recesses may be arranged in very thin intermediate disks when the disk parts contact each other exclusively at the spacers. According to this embodiment, each of the first and second disk parts requires depressions that correspond to half of the depth of the recesses. Further, this construction allows the disk parts to be machined by cutting in a simple manner to a given extent after casting. The first and second disk parts according to the this embodiment contact one another so that they adjoin at the machined locations.
The connection of the first and second disk parts may comprise a weld. However, heat warping caused by welding may be prevented by riveting the first and second disk parts to one another.
The intermediate disk according to the present invention may be assembled simply when the first and second disk parts are pretensioned relative to one another by clamps. Furthermore, a plurality of clamps may be connected via crosspieces or webs to form a clamping ring, for example, to reduce the quantity of structural component parts.
A given thickness of the intermediate disk according to the present invention may be adjusted when the spacers are constructed as a plurality of distance pieces arranged between the first and second disk parts. The distance pieces may have dimensions corresponding to the given thickness of the intermediate disk and may be exchanged to produce different thicknesses of the intermediate disks in building-block or modular form. The first and second disk parts may be inexpensively stamped from sheet metal in this construction.
The assembly of the intermediate disk according to the present invention may be especially economical when the spacers are constructed as distance pieces with integral rivets penetrating the first and second disk parts.
Assembly costs for the intermediate disk according to the present invention are further reduced when the spacers are constructed as web pieces of a corrugated ring arranged between the two disk parts.
According to another advantageous further development of the invention, the corrugated ring forms a positive radial engagement with the first and second disk parts when the corrugated ring has bars or clips penetrating into recesses of the first and second disk parts. This embodiment relieves the fastening elements required for connecting the disk parts.
According to another embodiment of the present invention, the corrugated ring is manufactured with fastening elements connecting the disk parts with one another when the clips of the corrugated ring are beaded or flanged so as to engage behind the disk parts. As a consequence of this construction, the assembly of the first and second disk parts may be automated.
According to another embodiment of the present invention, the carrying off of heat through the recesses is improved in that the spacers are constructed as air-conducting elements for guiding the air present between the disk parts.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.